Fin



FIG. 1 is perspective view of a fin, showing my new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevation view thereof shown on an enlarged scale;

FIG. 6 is a rear elevation view thereof shown on an enlarged scale; and,

FIG. 7 is a top and side front perspective view thereof. 

The ornamental design for a fin, as shown. 